The invention disclosed herein pertains generally to load binders, and more particularly to a lever-type load binder having improved safety features.
Load binders are used in a variety of situations to tension a chain or a wire, and are commonly used to secure large heavy loads, such as logs, to flatbed trucks.
Load binders known in the prior art are illustrated, for example, in U.S. Pat. No. 1,518,769 to Brunk. In the Brunk device ends of each of a pair of load engaging draw bars are pivotably connected at different points along a handle member. The device is tensioned by pivoting of the handle member. During the tensioning the handle acts as a lever to provide a mechanical advantage to draw the ends of the binder together. The tension is sustained by setting the device at a dead center. The device is released by rotating the lever in the opposite direction past dead center.
Various other types of load binders are disclosed in the following patents: U.S. Pat. No. 3,826,469 issued to Ratcliff et al; U.S. Pat. No. 3,842,426 issued to Ratcliff et al; U.S. Pat. No. 4,122,587 issued to Weiss et al; U.S. Pat. No. 398,714 issued to Farr; U.S. Pat. No. 1,972,346 issued to Julins; and U.S. Pat. No. 2,539,997 issued to Graves.
A serious problem encountered by users of conventional load binders is "flyback." That is, upon grasping the handle and initially pivoting the lever of a conventional load binder to release the tension, the user of the load binder may be subjected to the danger of being struck by the handle. This danger may arise because the handle is suddenly subjected to the tension force in the chain during release, and, if this tension force is large enough, it will cause the handle to pivot with considerable momentum. Since a user may pull the handle of the load binder toward himself in order to release the load binder, the user may thereby expose himself to the danger of "flyback," i.e., to the danger of being struck by the handle and/or lever pivoting toward the user in an uncontrolled manner.
The danger of flyback is exacerbated in the case of those users who mount lengths of pipe, called "cheaters," on the handles of conventional load binders. By using a cheater, a user effectively increases the length of the lever arm of the load binder, allowing the user to exert a larger tensioning force than he would otherwise be able to exert. As a consequence, however, the handle of the load binder will be subjected to a larger force when the load binder is initially released, resulting in the possibility that the handle and cheater will be propelled toward the user with even greater momentum.
Yet another problem associated with conventional load binders is the difficulty involved in releasing the load binder when the load binder has been used to subject a chain or wire to a relatively large tension. That is, because there is a relatively large tension force in the chain or wire, a user must exert a relatively large force on the handle of the load binder in order to release the load binder.
Accordingly, it is an object of the present invention to provide a simply and inexpensively constructed load binder which can be operated with an advanced degree of safety for the user.
It is another object of the present invention to provide a lever-type load binder which minimizes the danger of flyback.
It is yet another object of the present invention to provide a load binder wherein the actuating handle is used in conjunction with a separate lever element to tension the load binder and wherein the actuating handle may be selectively disengaged from the lever element and employed to trigger the release of the load binder.
It is still another object of the present invention is to provide a lever-type load binder which may be used to subject a chain or wire to a relatively large tension force, may be safely and securely locked in a tensioned configurations and may be released with relatively little effort.
These and other objects and features of the invention will become apparent from the claims and from the following description when read in conjunction with the accompanying drawings.